This disclosure is directed to an improved composite construction in game racquets. It can be used for racquetball, squash, tennis and other sports which utilize a stringed racquet.
Laminated wood racquets are believed outdated. Extruded metal frames utilizing aluminum and plastic inserts are disclosed in U.S. Pat. No. 4,066,260 of the same inventor. Such devices are exposed to rather rugged use and, therefore, must be fairly rigid. Even the gentlemanly play of racquet sports imparts fairly severe shock stresses to a racquet. There is, therefore, a tendency to deform the racquet frame during use. Deformation as a result of the continual pounding which occurs in use is resisted by the frame structure, provided it has the ability to absorb the energy that is created in use. When the racquet strikes a ball, the energy stored in the swinging racquet and the arm of the player places a substantial bending stress in the frame.
The referenced patent is directed to a composite, extruded metal channel which encloses or houses an extruded central core formed of plastic materials. The central core is attached to the surrounding metal channel by a suitable adhesive, thereby achieving a bonded material. This is said to provide improved strength and durability. The present invention is patentably different from the referenced disclosure. This invention is directed to a racquet which is much easier to manufacture and is made in a different manner.
Costs of manufacture are surprisingly high for molded composite material tennis racquets of equal playing characteristics. It is difficult to form racquets from a metal conduit or channel which is first bent into some particular shape and which is also bonded to the plastic core.
The apparatus of this disclosure is relatively easier to construct. One of the benefits of the present structure is the ability to form the laminated structure with reduced equipment costs. It is relatively more difficult and ordinarily more expensive in equipment and labor to bend channel material into the shape of a frame. The manufacturing cost of composite racquets known heretofore have been largely devoted to overcoming these fabrication difficulties. In particular, relatively greater manufacturing costs have been devoted to expensive molds. The present invention avoids the necessity of constructing that kind of mold. Rather, the aluminum section in this disclosure is first shaped to the desired frame size and shape; thereafter, open passages in the channel material are filled with the unset laminate material. The next step in the fabrication of the apparatus is to set the laminate material as by a combination of elevated pressure, elevated temperature and the passage of significant time.
This disclosure thus accomplishes composite material tennis racquet fabrication at a reduced cost and still has great frame structural integrity and ability to withstand the shock loading which occurs during use.
One feature of the present disclosure is to provide an extruded metal frame which supports multiple layers of laminated material. The laminated material is received in the extruded frame, thereby avoiding the necessity for more expensive molds. The composite frame is formed with a central metal webbing enabling quick and easy drilling of holes to string the racquet. The composite constructed frame has structural integrity enabling the frame to withstand the shock of rigorous use.